Apparatus for sterilizing and subsequently cooling food in closed containers



June 1, 1937. A K. oMsTED 2,082,460

APPARATUS FOR STERILIZING AND SUBSEQUENTLY COOLING FOOD IN CLOSED CONTAINERS Filed Jam` 9, 1953 Patented June l, 1937V UNITED STATES APPARATUS FOR STERILIZING AND-SUB- SEQUENTLYCOOLING FOOD IN CLOSED CONTAINERS Kaare Omsted, Oslo, Norway Application January 9, 1933, Serial No. .650,844 In Norway May A19, 1932 4 Claims.

` This invention relates to an apparatus for sterilizing and subsequently cooling food in closed containers, such as, for instance, containers of tin, glass or earthenware etc., the process being car- 5 ried out in a retort, in a liquid under pressure, the pressure in the retort being kept constant or approximately so during the sterilizing step or stage as well as during the cooling stage. By regulation of this pressure in such a way that it is equal to or greater than the internal pressure in the containers due to the expansion of the goods and the air in the containers as well as to development of steam in the same during the heating process, any danger 'of a bulging of bottom and lid of the containers or of other damage to or bursting of the same owing to the internal pressure is avoided. 'I'he pressure in the retort therefore should be maintained until the container with its contents has been cooled down substantially. f

According to the invention the retort during the sterilizing stage as well as the cooling stage is kept completely filled with liquid under pressure, during the sterilizing stage of the steam is supplied at a higher pressure than 'the Work.- ing pressure of the retort, this admission of steam being regulated in accordance with the temperature in the retort; during the cooling process cooling Water at a pressure equal-to or higher than 30 the working pressure is introduced into the retort.

For compensating for possible drop in pressure during operation a container is provided communicating with the retort, in which container a quantity of liquid is accumulated under 3,-, a hydraulic pressure or air pressure, equal to.

the working pressure of the retort. In the event of a drop in pressure in the retort part of the liquid in the said container then immediately will flow over into the retort and substantially '40 restore the pressure in the same.

The said container may be of the closed type, into which liquid from the retort ows when the retort is being put under pressure, whereby the air in the container is compressed and conse- 45 quently immediately will force some liquid back into the retort if the pressure in thesame for some reason or other should fall. The container may be a dome located directly on the retort or it may communicate with the retort 50 through a suitable conduit, in which latter case a. Water seal preferably is provided'in the conduit in order. to prevent steam from the retort from entering the container.

Instead of utilizing air pressure in the con- 55 tainer, the container may be located lat a height above the retort corresponding tothe working pressure in the same. In this case also a water seal should be providedr in the conduit between the retort and the container so as to prevent loss of heat by a flow of hot water up into the con- 5 tainer as well as to prevent steam from entering the same.

The steam supply to the retort is suitably controlled by a temperature regulator whilst the building up of excessive pressure in the retort is 10f prevented by means of a weightor spring-loaded overowor relief-valve.

When the sterilizing stage is inished the steam supply is cut oi and cooling water supplied to the retort, whereby the 'sterilizing nquid is dis- 15 placed or forced out of the retort, preferably throughthe said relief valve to a container in .which the liquid is accumulated, and from which it is returned to the `retort for the next sterilizing stage. When the cooling stage is iinished the 20 cooling water is drained olf and the retort opened for removal of the sterilized vgoods and for new charging.

By using a separate container for the accumulation of the displaced sterilizing liquid it is pos-` sible in retorts of the horizontal type, to use a liquid for sterilizing, inasmuch'as the once heated sterilizing liquid may be used over again repeatedly, whereby not only is a material saving of fuel effected, but the advantage is obtained that the restort can be fed with a liquid at a temperature approximating sterilizing temperature, especially as the container may be kept under a pressure above the atmospheric pressure and at a corresponding temperature, higher than 3'5 100 C. Contingently, steam may be supplied to the container in order to keep the temperature at the desired height. 'I'he container preferably is located above the retort so that! oil and fat carried into the retort with the tins oat to the top of the container from where it can be easily removed.

Finally the use of a separate container has the advantage that the steam pressure in the conl' tainer, as soon as the retort is reiilled, will apply an initial pressure to the liquid in the above described container or dome communicating with the retort.

The drawing illustrates diagrammatically an example of an embodiment of the invention. 5o

I is the retort and 2fan air-dome communicating with the retort through the water seal 3.. 'Ihe dome preferably is provided with a gauge -glass for the inspection of the water-level in the dome. The building up of excessive pres- 2 sure inthe retort is prevented by means of the weight-loaded relief or overflow valve 4 as will be brought out hereinafter. v

From the weight loaded relief or overow valve 4 a pipe I4 leads to the preferably isolated hot- Water container I6 supported above the retort on frames I5, a non-return valve I1 being .inserted in the pipe. A second pipe I8,` provided with a stop valveI I9 leads from the valve 4 to the drain pipe L The heatingof the sterilizing liquid and the building up of pressure in the retort is effected by'means of steam supplied through the pipe 8, and regulated according to the temperature in Athe retort by a regulating valve 1, controlled by the temperature regulator 8. `The steam supply ypipe-lineiurther is tted with a by-pass-pipe 9,

and with the necessary valves I0, so that' the steam if necessary may be bypassed around the regulating valve'1. A stop-valve I I for the steam is tted at the inlet to the retort.

Upon completion of the sterilizing stage or step the steam supply is shut off and cooling water introduced into the retort through the pipe -I2, which `is provided with a stop-valve I3. If

a drop in pressure in the retort should take place upon closing oif the steam supply and the admission of the c ooling water, this drop in pressure will at once be compensated for by the compressed air in the dome 2 forcing a; quantity of liquid out of the dome back to the retort.

During the continued supply of cooling-water to the retort thewater will displace the, warm sterilizing-liquid and force the same through the 'relief valve 4 and the pipe I4 to the hotwater container I6, the stop valve I9 at this time being closed. The hot-water container I6 is provided with-a safety valve 2I to which is connected a pipe 22 leading to the discharge pipe 20 so, that steam and water may escape upon an excessive rise in pressure'in the hot-water container, especially in the event of the container being completely iilled. After transfer of the' sterilizing liquid from the retort to the container I6, thevalve I9 is opened s o as to enable the introductionl of cooling water to the retort to be continued,v the `non-return valve I1 preventing back ilow of liquid from the container I6.

When the cooling is completed, the coolingliquid is drained off from the retort through the valve 23 to the drain pipe' 20, whereupon the end cover of the retort is opened for removal of the sterilized goods and renewed charging.. For

the next sterilizing stage or operation the hot 7o cooling of food -in closed containers,

' means for supplying steam liquidfin the hot Water container I6 is returned to the retort through the -valve 24 and pipe 25.

The invention hereinbeforevdescribed is particularly advantageous if cans of aluminum are used, as thi's'material does not possess sufficient elasticity, if deformed, to recover its original shape when-` the. internal pressure of `the can is removed. Likewise the invention is of advantage with light glass-or earthen ware containers where there is danger of bursting if the outside pressure is removed before the container with its contents has been cooled down suiliciently to effect `a substantial reduction of the internal pressure. l What I claim is: 1. Apparatus for the sterilizing and subsequent comprising in combination a single retort containing a liquid,

' is compressed by to the liquid in said a container in communication with said retort.'

the retort and container.

a valve intermediate l said'valve opening when 4the cooling water is admitted to said 'retort to permit the displaced sterilizing iluid in said vretort to be forced into said container, and a valve controlled conduit connecting said container and retort for subse- 'quent'return of the displaced sterilizlng fluid to the retort.

2. Apparatus for the sterilizing and subsequent cooling ot food in closed containers, comprising in combination a single retort containing a liquid, meansV for supplying sterilizing steam to the liquid in said retort to sterllim the food in the containers and to build up a pressure in the re,

tort not less than the pressure in the sealed containers within said retort, means for thereafter supplying cooling watei-to said retort through the bottom thereof, a sealed container in com-- munication with said retort, a loaded valve inL termediate thertort and said sealed container, said valve opening when ythe cooling water is admitted to said retort to permit the sterilizing fluid in said retort to be displaced and forced into said container, and said retort and container for subsequent return of the displaced sterilizing fluid to the retort and a valve in said conduit.

3. Apparatus for the sterilizing and subsequent cooling of food in closed containers, comprising iii-combination a single retort for the closed containers, ,said retort adapted to contain water, means for supplying steam to said retort to build up a pressure therein not-'less than the pressure in the closed containers -in the retort, a container 4for receiving the sterilizin'g liquid from said retort, a connection between said retort and container, a relief valve in said connection for preventing the building up of excessive pressure in said retort. means for admitting cooling water to said retort to displace the sterilizlng water therein and force the same past said valve into said container, and an air dome in open communication with the retort the air in which the uid in the retort for counteracting fluctuations of the pressure in the retort.

4. Apparatus for the sterilizing and subsequent cooling of food in`closed containers, comprising in combination a single retort adapted to contain water, means' for supplying steam to said retort to sterilize the food in the containers and to build up a pressure in said retort sumcient to prevent deformation of the closed containers in the same, means for thereafter supplying cooling water to said retort at the bottom thereof,'

\ KAAREOMSTED.

a conduit connecting 

